内蒙古查干敖包铁-锌多金属矿床的地质特征及找矿方向

GEOLOGICAL CHARACTERISTICS AND PROSPECTING TARGETS OF THE QAGAN OBO Fe-Zn POLYMETALLIC DEPOSIT IN INNER MONGOLIA

查干敖包铁-锌多金属矿床矿区大地构造位置处于西伯利亚板块东南缘查干敖包-奥尤特-朝不楞早古生代构造-岩浆岩带东段.中奥陶统多宝山组是本区主要的赋矿地层,与铁、锌多金属成矿关系密切.在查干敖包闪长岩体和多宝山组浅海相沉积岩的接触部位,往往形成含铁-锌矿层及锰矿层的夕卡岩带,铁-锌矿体主要呈似层状、条带状和透镜体状分布于夕卡岩带中.查干敖包石英闪长岩体为铁-锌多金属成矿不仅提供了成矿物质,而且还提供了成矿流体和成矿动力.区域性NE向查干敖包-东乌旗深大断裂控制着本区岩体和多金属矿床的产出,NE和NW向的次级断裂和构造破碎带控制铁、锌矿体的产出.矿区及外围的中奥陶统多宝山组浅海相沉积岩与多期次中酸性岩浆侵入体接触带及围岩裂隙密集带,是寻找铁、锌多金属矿的主攻区域.

The Qagan Obo Fe-Zn polymetallic deposit tectonically lies in the eastern part of the Early Paleozoic Qagan Obo-Aoyoute-Chaobuleng tectonomagmatic belt.The Middle Ordovician Duobaoshan Formation,serving as the main host,is closely related to the metallogenesis.The skam zones with Fe-Zn and Mn layers commonly occur at the contact between Qagan Obo quartz diorite stock and the neritic facies sedimentary rocks of Duobaoshan Formation.The Fe-Zn orebodies are mainly hosted by the skarn in stratiform,banded or lenticular shapes.The Qagan Obo quartz diorite stock supplies not only the ore materials,but also the ore-forming fluid and dynamic.The regional NE-striking Qagan Obo-Dongwuqi deep fault controls the occurrences of rock bodies and polymetallic deposits.The secondary NE-and NW-trending fractures control the distribution Fe-Zn orebodies.The favorable areas for seeking Fe-Zn polymetallic deposits are the contact zones between the multi-staged acid-intermediate magmatic intrusions and the neritic facies sedimentary rocks of Middle Ordovician Duobaoshan Formation and the concentrated fissure belts in the wallrocks.